This single beam tetrode is an early all glass envelope design, probably from the late 1940's. The output is modest and the dissipation high in relation to the output. The other possible use would be as a frequency multiplier rather than a class C amplifier.

The wide glass tube envelope diameter is 30 mm, with a wider skirt, the overall length excluding B9G base pins, is 58 mm.

References: Datasheet & ¹⁰⁴⁰. Type VT510 was first introduced^¶ in 1947.

 
Pin Connections

B9G	1	2	3	4	5	6	7	8	9
	h	a	g2	g2	bp,s	k	g1	bp,s	h

 
Absolute Maximum Operating Conditions^¶

Beam Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	mAg	Pout	Pdiss	freq	f.max
	6.3	0.6	300	250	-50	44	6	0.4	7.7	7.5	60M	150

Thanks to Frank Philipse for supplying the above PDF datasheet